iommu: Change iommu driver to call unmap trace event
Change iommu driver to call unmap trace event. This iommu_map_unmap class
event can be enabled to trigger when iommu unmap iommu ops is called. Trace
information includes iova, physical address (map event only), and size.
Testing:
Added trace calls to iommu_prepare_identity_map() for testing some of the
conditions that are hard to trigger. Here is the trace from the testing: